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Metallomics and the Cell

Volume 12 of the series Metal Ions in Life Sciences pp 119-168

Date:

Intracellular Calcium Homeostasis and Signaling

  • Marisa BriniAffiliated withDepartment of Comparative Biomedicine and Food Sciences, University of Padova Email author 
  • , Tito CalìAffiliated withDepartment of Comparative Biomedicine and Food Sciences, University of Padova
  • , Denis OttoliniAffiliated withDepartment of Biomedical Sciences, University of Padova
  • , Ernesto CarafoliAffiliated withVenetian Institute of Molecular Medicine (VIMM) Email author 

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Abstract

Ca2+ is a universal carrier of biological information: it controls cell life from its origin at fertilization to its end in the process of programmed cell death. Ca2+ is a conventional diffusible second messenger released inside cells by the interaction of first messengers with plasma membrane receptors. However, it can also penetrate directly into cells to deliver information without the intermediation of first or second messengers. Even more distinctively, Ca2+ can act as a first messenger, by interacting with a plasma membrane receptor to set in motion intracellular signaling pathways that involve Ca2+ itself. Perhaps the most distinctive property of the Ca2+ signal is its ambivalence: while essential to the correct functioning of cells, Ca2+ becomes an agent that mediates cell distress, or even (toxic) cell death, if its concentration and movements inside cells are not carefully tuned. Ca2+ is controlled by reversible complexation to specific proteins, which could be pure Ca2+ buffers, or which, in addition to buffering Ca2+, also decode its signal to pass it on to targets. The most important actors in the buffering of cell Ca2+ are proteins that transport it across the plasma membrane and the membrane of the organelles: some have high Ca2+ affinity and low transport capacity (e.g., Ca2+ pumps), others have opposite properties (e.g., the Ca2+ uptake system of mitochondria). Between the initial event of fertilization, and the terminal event of programmed cell death, the Ca2+ signal regulates the most important activities of the cell, from the expression of genes, to heart and muscle contraction and other motility processes, to diverse metabolic pathways involved in the generation of cell fuels.

Keywords

apoptosis calcium calcium buffering proteins calcium sensor proteins calmodulin fertilization gene expression ion pumps mitochondria protein dephosphorylation protein phosphorylation Please cite as: Met. Ions Life Sci. 12 (2013) 119–168